WASHINGTON – The White House implemented new sanctions against Iran Tuesday, as the US seeks to tighten the financial screws on the regime in Tehran.US President Barack Obama issued an executive order that carries out sanctions approved previously by Congress. The new measures include cracking down on the provision of goods, services and technology to those who help the regime’s repression of the Iranian people.Reuters contributed to this report.They also take a step toward imposing sanctions on Iran’s natural gas exports, in addition to the ones currently in place for petroleum.“This action is part of our comprehensive sanctions effort to apply pressure on the Iranian government to meet its international obligations with regard to its nuclear program,” US National Security Council spokesman Tommy Vietor said in a statement accompanying the sanctions announcement.“This sanctions effort has produced profound and demonstrable results.”But Mark Dubowitz, executive director of the Foundation for Defense of Democracies and a proponent of increased sanctions, said that while the sanctions have had a tremendous effect on the Iranian economy, “there’s no evidence to date that sanctions have changed the calculus of Iran’s leaders with respect to their pursuit of nuclear weapons.”Dubowitz described Tuesday’s action as mostly technical in nature. Still, he said, the signing of the executive order made a significant statement.“For the psychology of it, repetition is the key to success of message penetration,” he said.“If you’re going to send a message to the Iranian regime that the administration is serious about economically crippling them, then I think this executive order plays an important role.” He added that there was also a political message, as Obama wanted to seem “to be aggressive about the implementation of sanctions and is not just being dragged kicking and screaming by Congress,” as Republicans have made out.GOP White House challenger Mitt Romney also took on the topic of Iran Tuesday, telling CNN that he agreed with Prime Minister Binyamin Netanyahu’s assessment of how to limit Tehran.“My own test is that Iran should not have the capability of producing a nuclear weapon,” Romney said, echoing comments he made in a major foreign policy address on Monday. “I think that’s the same test that Binyamin Netanyahu would also apply.”He also endorsed the idea that lines should be set out regarding Iranian activity on its nuclear program.“There has to be a recognition that there are boundaries that the Iranians may not cross,” he said.Romney indicated that should Jerusalem attack Iran during his administration, “the actions of Israel would not come as a surprise to me” because there would be clear communication between the two countries. Asked by Wolf Blitzer whether he would support Israel if it launched a strike, Romney responded: “We have Israel’s back, both at the UN, but also military.”He stressed, however, that “we have a long way to go before military action may be necessary.”He continued, “Hopefully it’s never necessary. Hopefully, through extremely tight sanctions as well as diplomatic action, we can prevent Iran from taking a course which would lead to them crossing that line.”Romney reiterated to Blitzer his pledge that his first trip abroad as president would be to Israel.Romney has pulled ahead of Obama for the first time in more than a month and leads 45 percent to 44 percent among likely voters, according to a Reuters/Ipsos tracking poll released on Wednesday.The online survey of 1,027 likely voters was conducted between October 6 and October 10. The precision of the poll is measured using a credibility interval, which is plus or minus 3.5 percentage points for likely voters.